Some cranes are mounted in pairs on a

1、Isogonic lines are lines on a chart in

Isogonic lines are lines on a chart indicating （）.Apoints of equal variationBpoints of zero variationCthe magnetic latitudeDmagnetic di

2、（） are mounted in pairs to protect the

（） are mounted in pairs to protect the boiler against overpressure.ASafety valvesBWater tubesCSteam stop valvesDBlow down valve

3、On（）side of the street there are some

On（）side of the street there are some trees.AbothBeitherCeveryDall

4、You are in charge of a stand-on vessel

You are in charge of a stand-on vessel in a crossing situation.The other vessel is 1.5 miles to port.You believe that risk of collision exist...

5、The crane is usually mounted on a pede

The crane is usually mounted on a pedestal to offer adequate （） to the operator.AtimeBspaceClengthDvisibility

6、In some parks visitors are requested t

In some parks visitors are requested to keep（）the grass.AasideBawayCoutDoff